1. Field of the Invention
This invention relates generally to an apparatus for anchoring roof support plates to the roof of an underground construction and, more particularly, to apparatus for drilling the hole for the anchor rod, for filling the hole with a resin, and for inserting the anchor rod in the hole to secure the roof support plate.
2. Description of the Background
The technique of roof bolting or rock bolting as an alternative to conventional timbering for securing the roof of tunnels and mining excavations is known. In fact, specially designed operating units are presently available to accomplish the anchoring of roof support plates by rock bolting. In one of these known machines, an operating unit drills a bore hole in the roof and places an adhesively retained anchor in the drill hole. In such machine a sled is moveable longitudinally on a carriage and the sled carries a further transverse sled on which a rock drill and an anchor placement machine are mounted. A rotatable guide element that includes guides for the drill rod and the anchor as well as the feed hose for pneumatically blowing-in adhesive cartridges is located at the front end of the carriage of the sled. The rear end of the carriage includes elements for pressing a support plate against the roof to set an anchor rod therein.
In the operation of this previously known system, the guide element and the transverse sled are first moved so that the rock drill is aligned with the drill rod guide and then the bore hole is drilled in the roof using the rock drill. After withdrawal of the drill rod, the tube end is swung beneath the bore hole and the cartridges containing the adhesive are blown in with compressed air. Finally, the transverse sled and the guide element are moved so that the anchor placement machine that includes the anchor attached thereto is aligned with the bore hole. The anchor is then introduced and seated in the bore hole, where it is retained by the adhesive.
Although use of this known anchor drilling machine does make it possible to secure support plates to the roof of an underground excavation without employing manual labor to perform every step, the use of this automated machine is, nevertheless, tedious and requires much setting up and skill in operation. In addition, because of the separate units employed considerable space is required for this machine and, for that reason, it is not suitable for the simultaneous placement of a large number of anchor rod into a support plate at one time.
In addition to the anchor drilling unit described above, other anchor drilling units are known, such as those in U.S. Pat. No. 4,158,520, U.S. Pat. No. 4,588,037, and in Published German Pat. No. 2,657,650. Nevertheless, these previously known rock bolting or anchor drilling units also suffer from at least the above-mentioned disadvantages.